This application is based on and claims priority of Japanese Patent Application Nos. Hei. 8-12410 filed on Jan. 29, 1996, Hei. 8-76631 filed on Mar. 29, 1996, Hei. 8-75906 filed on Mar. 29, 1996, Hei. 8-75692 filed on Mar. 29, 1996, Hei. 8-77157 filed on Mar. 29, 1996, Hei. 8-81452 filed on Apr. 3, 1996, Hei. 8-150870 filed on Jun. 12, 1996, Hei. 8-228274 filed on Aug. 29, 1996, and Hei. 8-334092 filed on Dec. 13, 1996, the contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to a cooling apparatus using boiling and condensing refrigerant, in which refrigerant is boiled by heat of a high temperature medium and is then condensed so as to radiate heat of the high temperature refrigerant, such as a cooling apparatus having a thermosyphon type heat exchanger.
2. Description of the Prior Art
Conventionally, heating elements such as electronic parts are occasionally housed in a closed housing. In this case, as a method for cooling the heating elements, there has been employed a method in which heat exchange is performed between air inside the housing and air outside the housing, because the outside air cannot be directly taken into the housing so as to ventilate the interior of the housing. As a method for obtaining a small number of parts and a large amount of heat movement, there has been known a method using heat pipes (in which a refrigerant is sealed) disposed so as to pass through a housing, as disclosed in JP-B2-2-3320.
In the heat pipe as disclosed in JP-B2-2-3320, the inside refrigerant is boiled by the high-temperature air in the housing, the refrigerant is condensed by the radiating portion disposed outside the housing so as to radiate the heat, and the condensed refrigerant again drops into the heat absorbing portion disposed within the housing.
However, in the heat pipe as disclosed in JP-B2-2-3320, vaporized refrigerant which has been boiled and rises and condensed refrigerant which has been condensed descends within the same pipe. Therefore, the flowing directions of the refrigerants are opposed to each other, and there may cause a problem in that the entire refrigerant does not circulate efficiently.
In view of the foregoing, there has been also known a cooling apparatus using boiling and condensing refrigerant in which the heat can be efficiently radiated by circulating the refrigerant, as in JP-U-62-162847. According to the cooling apparatus disclosed in JP-U-62-162847, a heating element is secured to a refrigerant tank, heat generated by the heating element is absorbed by a refrigerant sealed in the refrigerant tank, the refrigerant boiled and vaporized by the heat absorption is condensed and liquefied by a radiator disposed on the refrigerant tank, and the condensed and liquefied refrigerant is returned to the refrigerant tank through a refrigerant return pipe inserted into the refrigerant tank.
However, in the cooling apparatus disclosed in JP-U-62-162847, since the refrigerant return pipe for returning the refrigerant condensed by the radiator to the refrigerant tank is inserted into the refrigerant, the refrigerant may be heated within the refrigerant return pipe before returning back into the refrigerant tank, the buoyancy in the upward direction is exerted on the refrigerant, and the refrigerant does not return back into the refrigerant tank efficiently. As a result, there occurs a problem in that the refrigerant circulates slowly and the radiating performance deteriorates.
Further, in the case where a passage for communicating between the refrigerant tank and the radiator is cooled when the refrigerant boiled and vaporized from the refrigerant tank rises to the upper radiator, the boiled and vaporized refrigerant is condensed in the passage and drops down before moving to the radiator. As a result, there occurs a problem in that the refrigerant circulates slowly and the radiating performance deteriorates.
Further, by the deterioration of the radiating characteristics, the cooling apparatus becomes large-sized.
The present invention has been accomplished on the basis of the aforementioned circumstances. A first object of the present invention is to downsize the cooling apparatus by employing a new construction.
A second object of the present invention is to provide a cooling apparatus, capable of preventing the circulation of the refrigerant from being impeded.
A third object of the present invention is to provide a cooling apparatus, having a low-temperature-side communication pipe for returning refrigerant condensed by a radiator to a refrigerant tank and capable of preventing an occurrence of an ascending force of the condensed refrigerant within the low-temperature-side communication pipe when the heating of the low-temperature-side communication pipe is heated.
A fourth object of the present invention is to provide a cooling apparatus, having a high-temperature-side communication pipe for sending refrigerant boiled by a refrigerant tank to a radiator and capable of preventing vaporized refrigerant from being condensed within the high-temperature-side communication pipe when the cooling of the high-temperature-side communication pipe is cooled.
According to an aspect of the present invention, a refrigerant sealed in a refrigerant tank receives heat of a high-temperature portion and becomes boiled and vaporized. The boiled and vaporized refrigerant ascends and flows into a radiator. In the radiator, heat of the vaporized refrigerant is radiated to a low-temperature portion to condense and liquefy the refrigerant. The condensed and liquefied refrigerant returns to the refrigerant tank through a communication pipe and receives heat again. In the present invention, the circulation of the refrigerant is prevented from being impeded in order that a heat conduction between either one of the refrigerant tank, the radiator, the high temperature portion and the lower temperature portion, and the heat conduction to the communication pipe is suppressed by heat conduction suppressing means.
That is, when the heat conduction suppressing means suppresses the heat conduction between the refrigerant tank and the communication pipe, the descending refrigerant which has been condensed and liquefied by the radiator absorbs high-temperature heat from the refrigerant tank through the communication pipe to prevent from receiving the ascending force within the communication pipe. When the heat conduction suppressing means suppresses the heat conduction between the high temperature portion and the communication pipe, the descending refrigerant which has been condensed and liquefied by the radiator absorbs heat from the high-temperature portion through the communication pipe to prevent from receiving the ascending force within the communication pipe.
Further, when the heat conduction suppressing means suppresses the heat conduction between the radiator and the communication pipe, the ascending refrigerant which has been boiled and vaporized in the refrigerant tank can be prevented from descending within the communication pipe by radiating heat to the low-temperature radiator through the communication pipe. Further, when the heat conduction suppressing means suppresses the heat conduction between the low temperature portion and the communication pipe, the ascending refrigerant which has been boiled and vaporized in the refrigerant tank can be prevented from descending within the communication pipe by radiating heat to the low-temperature portion through the communication pipe.
As a result, since the radiation can be performed efficiently, the cooling apparatus can be downsized.
According to another aspect of the invention, the refrigerant sealed into the refrigerant tank receives heat of a high-temperature fluid and becomes boiled and vaporized. The boiled and vaporized refrigerant is delivered to a radiator disposed away from a fluid separating plate. In the radiator, heat of the refrigerant is radiated to a low-temperature fluid so as to be condensed and liquefied the refrigerant. The condensed and liquefied refrigerant returns to the refrigerant tank through the communication pipe and receives heat again. In this way, it is possible to prevent the circulation of the refrigerant from being impeded, since the heat conduction between either one of the refrigerant tank, the radiator, the high-temperature portion and the low-temperature portion,and the communication pipe is suppressed by the heat conduction suppressing means.
The heat conduction suppressing means may be a refrigerant tank-side heat insulating material disposed between the refrigerant- tank and the low-temperature-side communication pipe and formed of a heat insulating material. In this way, the heat conduction from the refrigerant tank to the low-temperature-side communication pipe can be suppressed. As a result, it is possible to prevent the descending refrigerant which has been condensed and liquefied by the radiator from absorbing heat from the high-temperature refrigerant tank through the communication pipe and receiving the ascending force in the low-temperature-side communication pipe. Accordingly, it is possible to prevent the circulation of refrigerant from being impeded, and the cooling apparatus can be downsized.
The heat conduction suppressing means may be a radiator-side heat insulating material disposed between the radiator and the high-temperature-side communication pipe and formed of a heat insulating material. In this way, it is possible to prevent the ascending refrigerant which has been boiled and liquefied in the refrigerant tank from radiating heat to the low-temperature radiator through the communication pipe and descending in the communication pipe. Further, it is possible to prevent the circulation of refrigerant from being impeded, and the apparatus can be downsized.
The heat conduction suppressing means may be a high-temperature portion-side heat insulating material covered on an outer periphery of the low-temperature-side communication pipe and formed of a heat insulating material. In this way, it is possible to suppress the heat conduction from the high-temperature portion to the low-temperature-side communication pipe. As a result, it is possible to prevent the descending refrigerant which has been condensed and liquefied in the radiator from absorbing heat from the high-temperature portion through the low-temperature-side communication pipe and receiving the ascending force in the low-temperature-side communication pipe. Further, it is possible to prevent the circulation of refrigerant from being impeded, and the cooling apparatus can be downsized.
The heat conduction suppressing means may be a low temperature portion-side heat insulating material covered on an outer periphery of the high-temperature-side communication pipe and formed of a heat insulating material coated. In this way, it is possible to prevent the ascending refrigerant which has been boiled and vaporized in the refrigerant tank from radiating heat to the low-temperature portion through the high-temperature-side communication pipe and descending in the high-temperature-side communication pipe. Further, it is possible to prevent the circulation of refrigerant from being impeded, and the cooling apparatus can be downsized.
Further, the above heat insulating material may cover at least a part of the outer periphery of the low-temperature-side communication pipe or the high-temperature-side communication pipe. In this way, it is possible to prevent the circulation of refrigerant from being impeded, and the cooling apparatus can be downsized as compared with prior art.
Still further, the above heat insulating material may cover the entire outer periphery of the low-temperature-side communication pipe or the high-temperature-side communication pipe. In this way, it is possible to further prevent the circulation of refrigerant from being impeded, and the cooling apparatus can be downsized as compared with the prior art.
Further, the heat insulating material may be formed of a foaming resin; and therefore, heat insulation can be performed efficiently.
The heat conduction suppressing means may include a high-temperature-side partition member for partitioning a high-temperature passage with the fluid separating plate so that the low-temperature-side communication pipe is separated to a region, a temperature of which is lower than that in the high-temperature-side passage. It is possible to suppress the heat conduction from the high-temperature passage to the low-temperature-side communication pipe. As a result, it is possible to prevent the descending refrigerant which has been condensed and liquefied in the radiator from absorbing heat from the high-temperature passage through the low-temperature-side communication pipe and receiving the ascending force in the low-temperature-side communication pipe. In this way, it is possible to prevent the circulation of refrigerant from being impeded, and the cooling apparatus can be downsized.
Further, the heat conduction suppressing means may include a low-temperature-side partition member for partitioning a low temperature passage with the fluid separating plate so that the high-temperature-side communication pipe is separated to a region, a temperature of which is higher than that in the low-temperature-side passage. In this way, it is possible to prevent the ascending refrigerant which has been boiled and liquefied in the refrigerant tank from radiating heat to the low-temperature passage through the high-temperature-side communication pipe and descending in the high temperature-side communication pipe. In this way, it is possible to prevent the circulation of refrigerant from being impeded, and the cooling apparatus can be downsized.
Further, a plurality of boiling and cooling units are disposed so that refrigerant tanks are disposed in parallel with each other and radiators are disposed in parallel with each other. In addition, there may be provided a high-temperature-side partition member for partitioning a high-temperature passage with the fluid separating plate and a low-temperature-side partition member for partitioning a low-temperature passage with the fluid separating plate, and the low-temperature-side communication pipe is separated to a region,t a temperature of which is lower than that in the high-temperature passage by the high-temperature-side partition member and the low-temperature-side partition member and the high-temperature-side communication pipe is separated to a region, a temperature of which is higher than that in the low temperature passage. In this way, the heat transfer from the high temperature passage to the low-temperature-side communication pipe and the heat transfer from the high-temperature-side communication pipe to the low temperature passage can be suppressed, respectively.
As a result, it is possible to prevent the descending refrigerant which has been condensed and liquefied in the radiator from absorbing heat from the high-temperature passage through the low-temperature-side communication pipe and receiving the ascending force in the low-temperature-side communication pipe, and it is also possible to prevent the refrigerant which has been boiled and vaporized in the refrigerant tank from radiating heat to the low-temperature passage through the high-temperature-side communication pipe and descending in the high-temperature-side communication pipe.
Accordingly, it is possible to prevent the circulation of refrigerant from being impeded, and the cooling apparatus can be downsized.
The low-temperature-side communication pipe may be disposed substantially in parallel with the heat absorbing pipe so as to communicate a heat absorbing-side lower communication portion with a radiating-side lower communication portion, and the high-temperature-side communication pipe may be disposed substantially in parallel with the radiating pipe so as to communicate a heat absorbing-side upper communication portion with a radiating-side upper communication portion. Since the heat conduction suppressing means may be provided on the low-temperature-side communication pipe or the high-temperature-side communication pipe, it is possible to suppress the heat conduction from the refrigerant tank to the low-temperature-side or the heat conduction from the high-temperature-side communication pipe to the radiator. As a result, it is possible to prevent the descending refrigerant which has been condensed and liquefied in the radiator from absorbing heat from the high-temperature refrigerant tank through the communication pipe and receiving the ascending force in the low-temperature-side communication pipe. It is possible to prevent the ascending refrigerant which has been boiled and vaporized in the refrigerant tank from radiating heat to the low-temperature radiator through the communication pipe and descending in the communication pipe.
In this way, it is possible to prevent the circulation of refrigerant from being impeded, and the cooling apparatus can be downsized.